The proposed study concerns the father's role in his adolescent son's use of tobacco and marijuana. The study has two foci: (1) A specification of paternal factors (paternal personality/attitudinal attributes, paternal child-rearing practices, and the extent to which the father serves as a role model for his son) which may influence his son's drug behavior and (2) An interrelationship approach which requires examination not only of the paternal dimensions alone but in interaction with the adolescent's own personality and the family system. The paternal factors alone and in interaction will be examined in relation to the son's a) choice of drugs and b) mild versus heavy use of tobacco and marijuana. The sample will consist of 300 male adolescents and their fathers. Self-administered questionnaires will be given in the Spring of 1980. Our instruments will include scales of adequate psychometric properties to measure the following areas: paternal and adolescent personality attributes, paternal and maternal child-rearing practices, paternal identification, family relations, and peer dimensions. In addition, there will be extensive questions on demographics, self-drug use by significant others in the adolescent's environment. Multivariate techniques of analysis will be used to examine the data. The significance of the study lies in its attempt to examine a greatly underresearched area--the role of the father in his son's drug behavior. Such a study is necessary to help balance the research which already exists on maternal, peer, and personality factor related to drug use. In addition, by examining paternal factors in the context of these other crucial variables, we hope to obtain a more thorough understanding of the correlation of adolescent drug behavior so that efforts at both prevention and treatment can be specified in ways heretofore not possible.